This invention relates generally to hydrotherapy and more particularly to an improved method and apparatus useful in spas, hot tubs, bathtubs, and the like for discharging a fluid (e.g. water-air) stream to impact against and massage a user's body.
Applicants' grandparent application Ser. No. 843,151 filed Mar. 24, 1986, now U.S. Pat. No. 4,679,258, discloses a method and apparatus for discharging a fluid stream, while concurrently translating the stream along a substantially random path. A user is thus able to fixedly position his body proximate to the apparatus to enable the discharged stream to impact against and sweep over an area of the user's body. In a typical application, the apparatus is mounted in an opening in the peripheral wall (i.e. including floor) of a spa, hot tub, bathtub, etc., generically referred to as a water tub. The apparatus includes a housing which can be formed integral with the tub wall but which more typically comprises a separate box-like structure adapted to be mounted adjacent to the rear face of the wall and accessible through the wall opening.
A preferred embodiment of said U.S. Pat. No. 4,679,258 is characterized by the use of a water-air jet assembly including a nozzle for discharging a water jet under pressure into a mixing cavity. The water jet creates a suction, via venturi action, which draws air into the cavity and the resulting water-air stream is then discharged into an elongated rigid conduit having a tubular supply section, a tubular discharge section, and a tubular intermediate section coupling said supply section to said discharge section. The conduit is open at both ends having a supply orifice at its supply section end and a discharge orifice at its discharge section end. The conduit is shaped such that the intermediate section axis deviates by an acute angle from the supply section axis. The axes of the supply and intermediate sections define a plane and the axis of the discharge section deviates by an acute angle from that plane. The supply bore defining said supply orifice. The ball is accommodated for swivel movement within a socket with the supply orifice open to the aforementioned mixing cavity. The conduit discharge end is left free to move within the tub wall opening across a substantially planar area roughly approximating an extension of the tub wall. The water-air stream is discharged from the discharge orifice in a direction having a primary massage component extending substantially perpendicular to the planar area and having a secondary thrust component extending substantially parallel to the planar area. The thrust component produces a lateral force for moving the discharge end along a path coincident with said planar area. The boundary of the planar area is substantially defined by a thrust modifier means in the form of a frame, which cooperates with a pivot pin secured to said conduit. The frame includes a series of open recesses, each intended to momentarily capture the pivot pin, as the conduit discharge end moves toward the area boundary. With the pivot pin so captured, the stream thrust component acts to rotate the discharge end around the pivot pin and thereby redirect the thrust component enabling the pivot pin to withdraw from its open recess and initiate a new traverse across the frame. Thus, the discharge orifice will traverse a path comprised of small substantially semicircular path segments, each described when the pivot pin is engaged in a recess, linked by longer translational path segments extending between recesses. The translational recess-to-recess path segments extend substantially across the frame and occur in an essentially random unpredictable pattern.
Applicants' parent application 072,409 discloses that in the aforedescribed embodiment of said U.S. Pat. No. 4,679,258, in the event the air inlet to the mixing cavity becomes obstructed (either intentionally or inadvertently), the suction created in the cavity can act to increase the drag, i.e. friction loss, between the conduit and its mounting means. As a result, the movement of the conduit discharge orifice may become sluggish.
Applicants' U.S. Pat. No. 4,715,071 discloses a hydrotherapy apparatus in which a passageway is provided around the swivel mounting of the conduit supply end for passing water from outside the conduit into the mixing cavity of the apparatus. As discussed therein, this action mitigates the effect of the suction force produced in the mixing cavity acting on the conduit itself.